# Room temperature test of the Continuous Spontaneous Localization model using a levitated micro-oscillator

## TL;DR

This study demonstrates a room-temperature levitated micro-oscillator experiment that sets new upper bounds on the CSL collapse rate, showing promise for future collapse model tests.

## Contribution

First proof-of-principle experiment using a magneto-gravitational levitated micro-oscillator to test CSL at room temperature, improving bounds significantly.

## Key findings

- Set two orders of magnitude better upper bounds on CSL collapse rate.
- Achieved partial sensitivity to the enhanced collapse rate proposed by Adler.
- Showed advantages of room-temperature operation over low-temperature experiments.

## Abstract

The Continuous Spontaneous Localization (CSL) model predicts a tiny break of energy conservation via a weak stochastic force acting on physical systems, which triggers the collapse of the wave function. Mechanical oscillators are a natural way to test such a force; in particular levitated micro-mechanical oscillator has been recently proposed to be an ideal system. We report a proof-of-principle experiment with a micro-oscillator generated by a micro-sphere diamagnetically levitated in a magneto-gravitational trap under high vacuum. Due to the ultra-low mechanical dissipation, the oscillator provides a new upper bound on the CSL collapse rate, which gives an improvement of two orders of magnitude over the previous bounds in the same frequency range, and partially reaches the enhanced collapse rate suggested by Adler. Although being performed at room temperature, our experiment has already exhibits advantages over those operating at low temperatures previously reported. Our results experimentally show the potential of magneto-gravitational levitated mechanical oscillator as a promising method for testing collapse model. Further improvements in cryogenic experiments are discussed.